1. Field of the Invention
The present invention relates to an attachment structure of a bumper beam for an automobile.
2. Description of the Related Art
An example of the attachment structure of a bumper beam for an automobile is disclosed in Japanese Patent Unexamined Publication No. Hei. 7-304462 (JP-A-7-304462) entitled xe2x80x9cFront body structure of automobilexe2x80x9d, for example. According to this conventional art, this body structure is arranged in a manner that a front module (a bulk head, a bumper beam, a bumper face, a front grill, a head light brackets) is coupled to a front body frame of an automobile. This body structure will be explained with reference to the main portion of the front body structure for an automobile of the publication shown in FIG. 8. In FIG. 8, the reference numerals of the constituent elements of the front body structure are renumbered.
FIGS. 8A and 8B are diagrams for explaining the problem of the conventional attachment structure of a bumper beam.
FIG. 8A shows the structure same as shown in the publication, wherein a flange 102 is fixed to the front end of a side member 101, and an attachment bracket 105 for a bulk head 103 and a bumper beam 104 is attached to the flange 102 by means of formally fastening bolts 106.
FIG. 8B shows the case where the impact is applied to the bumper beam 104. When the impact force F acts on the bumper beam 104, the impact force F is directly applied to the side member 101 from the bumper beam 104, so that the side member 101 may be deformed.
In this manner, when the side member 101 (body frame) is deformed, it is required to exchange the bumper beam 104 and repair the body frame. Thus, a lot of trouble is required for the exchanging and the repairing.
There is a method of making the size of the bumper beam 104 longer in order to prevent the deformation of the side member 101. However, in this case, since the protruded length (overhang amount) of the bumper beam 104 becomes large, the degree of the freedom at the time of designing the front or rear portion is lowered.
Accordingly, an object of the invention is to provide the attachment structure for a bumper beam which can easily repair and improve the degree of the freedom of the design.
In order to attain the aforesaid object, the invention according to a first embodiment is arranged in a manner that in an attachment structure of a bumper beam in which a bumper stay is attached to an end portion of each of front side frames or rear side frames of an automobile and a bumper beam is attached to the bumper stays, the attachment structure of a bumper beam comprises each of the bumper stays formed as a combined unit formed by an impact absorbing member which is deformed to absorb impact when impact force is applied to the bumper beam and a holding member having rigidity larger than the impact absorbing member, the holding members are attached to the end portions of the rear side frames or the front side frames, the holding member is combined with the impact absorbing member, and the bumper beam is attached to the impact absorbing members.
In this manner, each of the bumper stays is formed as the combined unit formed by the impact absorbing member and the holding member, and the holding member having the rigidity larger than the impact absorbing member is attached to the frame side. When the impact force acts on the bumper beam, the impact absorbing member is deformed to absorb the impact. In contrast, the holding member is not deformed to protect the frame side. As a result, when repairing the bumper, it is required to merely exchange the impact absorbing members together with the bumper beam.
Further, since the impact absorbing members can efficiently absorb the impact and the holding member can distribute the impact acting on the frame, the overhang amount of the bumper beam can be made small and so the degree of the freedom at the time of designing can be improved.
According to a second embodiment of the present invention, in the attachment structure of the first embodiment, the holding member is formed by an extruded member whose sectional configuration is uniform in axial direction thereof.
Since the holding members can be manufactured continuously, the manufacturing efficiency of the holding members can be improved.
Further, since the holding member is formed by the extruded member, the thickness of the holding member is made large only at the portion where a large stress is applied but small at the portions where a small stress is applied. As a result, the holding member can be light-weight.